[PATCH] swsusp: make image size limit tunable

Make the suspend image size limit tunable via /sys/power/image_size.

It is necessary for systems on which there is a limited amount of swap
available for suspend.  It can also be useful for optimizing performance of
swsusp on systems with 1 GB of RAM or more.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/power/disk.c

@@ -365,9 +365,29 @@ out:
 
 power_attr(resume);
 
+static ssize_t image_size_show(struct subsystem * subsys, char *buf)
+{
+	return sprintf(buf, "%u\n", image_size);
+}
+
+static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n)
+{
+	unsigned int size;
+
+	if (sscanf(buf, "%u", &size) == 1) {
+		image_size = size;
+		return n;
+	}
+
+	return -EINVAL;
+}
+
+power_attr(image_size);
+
 static struct attribute * g[] = {
 	&disk_attr.attr,
 	&resume_attr.attr,
+	&image_size_attr.attr,
 	NULL,
 };